Heated Glass Element: Description and Operation

Rear Window Defogger

How the Circuit Works
Voltage is applied at all times through fuse 11 (in the under-hood fuse/relay box) to the rear window defogger relay contacts. With the ignition switch ON (II), voltage is applied through fuse 14 (in the under-dash fuse/relay box) to the rear window defogger relay coil.

When you push the defogger switch (in the climate control unit) once, a path to ground is provided by the climate control unit to the rear window defogger relay. The defogger ON indicator light comes on and the rear window relay contacts close. Voltage is applied to the defogger grid on the inside surface of the rear window, and the grid heats the rear window to remove any fog from the glass.

You can turn the defogger off by pushing the defogger switch a second time or by turning the ignition switch to LOCK (0). A timer in the climate control unit will automatically turn the defogger off after it has been on continuously for about 15 minutes.